fix GVN trying to transmute pointers to integers

This commit is contained in:
Ralf Jung 2024-10-05 17:05:47 +02:00
parent a8f9a32650
commit 7d63efdb8c
3 changed files with 31 additions and 15 deletions

View File

@ -103,7 +103,7 @@
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_span::DUMMY_SP;
use rustc_span::def_id::DefId;
use rustc_target::abi::{self, Abi, FIRST_VARIANT, FieldIdx, Size, VariantIdx};
use rustc_target::abi::{self, Abi, FIRST_VARIANT, FieldIdx, Primitive, Size, VariantIdx};
use smallvec::SmallVec;
use tracing::{debug, instrument, trace};
@ -568,13 +568,29 @@ fn eval_to_const(&mut self, value: VnIndex) -> Option<OpTy<'tcx>> {
CastKind::Transmute => {
let value = self.evaluated[value].as_ref()?;
let to = self.ecx.layout_of(to).ok()?;
// `offset` for immediates only supports scalar/scalar-pair ABIs,
// so bail out if the target is not one.
// `offset` for immediates generally only supports projections that match the
// type of the immediate. However, as a HACK, we exploit that it can also do
// limited transmutes: it only works between types with the same layout, and
// cannot transmute pointers to integers.
if value.as_mplace_or_imm().is_right() {
match (value.layout.abi, to.abi) {
(Abi::Scalar(..), Abi::Scalar(..)) => {}
(Abi::ScalarPair(..), Abi::ScalarPair(..)) => {}
_ => return None,
let can_transmute = match (value.layout.abi, to.abi) {
(Abi::Scalar(s1), Abi::Scalar(s2)) => {
s1.size(&self.ecx) == s2.size(&self.ecx)
&& !matches!(s1.primitive(), Primitive::Pointer(..))
}
(Abi::ScalarPair(a1, b1), Abi::ScalarPair(a2, b2)) => {
a1.size(&self.ecx) == a2.size(&self.ecx) &&
b1.size(&self.ecx) == b2.size(&self.ecx) &&
// The alignment of the second component determines its offset, so that also needs to match.
b1.align(&self.ecx) == b2.align(&self.ecx) &&
// None of the inputs may be a pointer.
!matches!(a1.primitive(), Primitive::Pointer(..))
&& !matches!(b1.primitive(), Primitive::Pointer(..))
}
_ => false,
};
if !can_transmute {
return None;
}
}
value.offset(Size::ZERO, to, &self.ecx).discard_err()?

View File

@ -23,19 +23,19 @@ Number of file 0 mappings: 6
- Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
Function name: closure_macro::main::{closure#0}
Raw bytes (35): 0x[01, 01, 03, 01, 05, 05, 0b, 09, 00, 05, 01, 10, 1c, 03, 21, 05, 04, 11, 01, 27, 02, 03, 11, 00, 16, 00, 00, 17, 00, 1e, 07, 02, 09, 00, 0a]
Raw bytes (35): 0x[01, 01, 03, 01, 05, 05, 0b, 09, 0d, 05, 01, 10, 1c, 03, 21, 05, 04, 11, 01, 27, 02, 03, 11, 00, 16, 0d, 00, 17, 00, 1e, 07, 02, 09, 00, 0a]
Number of files: 1
- file 0 => global file 1
Number of expressions: 3
- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
- expression 1 operands: lhs = Counter(1), rhs = Expression(2, Add)
- expression 2 operands: lhs = Counter(2), rhs = Zero
- expression 2 operands: lhs = Counter(2), rhs = Counter(3)
Number of file 0 mappings: 5
- Code(Counter(0)) at (prev + 16, 28) to (start + 3, 33)
- Code(Counter(1)) at (prev + 4, 17) to (start + 1, 39)
- Code(Expression(0, Sub)) at (prev + 3, 17) to (start + 0, 22)
= (c0 - c1)
- Code(Zero) at (prev + 0, 23) to (start + 0, 30)
- Code(Counter(3)) at (prev + 0, 23) to (start + 0, 30)
- Code(Expression(1, Add)) at (prev + 2, 9) to (start + 0, 10)
= (c1 + (c2 + Zero))
= (c1 + (c2 + c3))

View File

@ -31,19 +31,19 @@ Number of file 0 mappings: 6
- Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
Function name: closure_macro_async::test::{closure#0}::{closure#0}
Raw bytes (35): 0x[01, 01, 03, 01, 05, 05, 0b, 09, 00, 05, 01, 15, 1c, 03, 21, 05, 04, 11, 01, 27, 02, 03, 11, 00, 16, 00, 00, 17, 00, 1e, 07, 02, 09, 00, 0a]
Raw bytes (35): 0x[01, 01, 03, 01, 05, 05, 0b, 09, 0d, 05, 01, 15, 1c, 03, 21, 05, 04, 11, 01, 27, 02, 03, 11, 00, 16, 0d, 00, 17, 00, 1e, 07, 02, 09, 00, 0a]
Number of files: 1
- file 0 => global file 1
Number of expressions: 3
- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
- expression 1 operands: lhs = Counter(1), rhs = Expression(2, Add)
- expression 2 operands: lhs = Counter(2), rhs = Zero
- expression 2 operands: lhs = Counter(2), rhs = Counter(3)
Number of file 0 mappings: 5
- Code(Counter(0)) at (prev + 21, 28) to (start + 3, 33)
- Code(Counter(1)) at (prev + 4, 17) to (start + 1, 39)
- Code(Expression(0, Sub)) at (prev + 3, 17) to (start + 0, 22)
= (c0 - c1)
- Code(Zero) at (prev + 0, 23) to (start + 0, 30)
- Code(Counter(3)) at (prev + 0, 23) to (start + 0, 30)
- Code(Expression(1, Add)) at (prev + 2, 9) to (start + 0, 10)
= (c1 + (c2 + Zero))
= (c1 + (c2 + c3))